Martian Snow? Mars Orbiter Spots Dry Ice Snowflakes

While NASA’s Curiosity Rover explores the surface of the red planet the Mars Reconnaissance Orbiter is watching the planet from above. And the MRO has made an interesting discovery: It snows on Mars.

According to Fox News, the MRO discovered carbon dioxide snowflakes falling over Mars’ south pole in 2006. It was only discovered recently, however, while researchers were analyzing data from the space craft.

Paul Hayne, of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, said:

“These are the first definitive detections of carbon-dioxide snow cloud. We firmly establish the clouds are composed of carbon dioxide — flakes of Martian air — and they are thick enough to result in snowfall accumulation at the surface.”

According to the CS Monitor, Mars is the only planet in our solar system that has carbon dioxide snowflakes.

The researchers found the martian snow using the Mars Climate Sounder. One measurement was taken while looking at the clouds above the red planet. Another measurement was taken with the instrument pointed at the horizon.

David Kass, who co-authored the study, said:

“One line of evidence for snow is that the carbon-dioxide ice particles in the clouds are large enough to fall to the ground during the lifespan of the clouds… Another comes from observations when the instrument is pointed toward the horizon, instead of down at the surface. The infrared spectra signature of the clouds viewed from this angle is clearly carbon-dioxide ice particles, and they extend to the surface… By observing this way, the Mars Climate Sounder is able to distinguish the particles in the atmosphere from the dry ice on the surface.”

CBS reports that this isn’t the first time that snow has fallen on the red planet. In 2008, NASA observed water-ice snow, the same snow that falls on earth, falling from the sky above Mars.